A conventional fuel injection device for an internal combustion engine has; a common rail for storing a high pressure fuel; fuel injection valves for injecting the high pressure fuel from the common rail into respective cylinders of the engine; a fuel pump for sucking and pressurizing the fuel and supplying the high pressure fuel to the common rail; a fuel return path for returning a portion of the high pressure fuel from the common rail to a low pressure side (a fuel tank); an electromagnetic type depressurizing valve which will be operated to open the fuel return path when the vehicle is decelerated in order to quickly reduce the fuel pressure in the common rail.
The depressurizing valve is mounted to, for example, the common rail. In the fuel injection device, however, as disclosed in Japanese Patent Publication No. 2001-59459, the depressurizing valve is mounted to the fuel pump. The depressurizing valve has a flanged portion, at which a through hole is formed for inserting a bolt therethrough, and the depressurizing valve is fixed to the fuel pump by the bolt.
In the fuel injection device, as disclosed in Japanese Patent Publication No. H11-141428, a solenoid portion is fixed to a body member of a fuel injection valve by a retaining nut, wherein an electromagnetic valve portion thereof can be used as a depressurizing valve.
The depressurizing valve mounted to the common rail has a connector for receiving driving current. The connector is electrically connected to a driving circuit through a wire harness, when the common rail is mounted to the engine. It is, however, necessary to adjust a direction of the connector when the depressurizing valve is mounted to the common rail, because the common rail must be mounted to the engine in a limited space and thereby a position (direction) of the connector must be selected to a predetermined position (direction) with respect to the common rail. Nothing has been proposed so far, wherein a direction of the connector is adjusted in the depressurizing valve to be mounted to the common rail.
If the fixing structure of the depressurizing valve, as disclosed in the above mentioned prior art (No. 2001-59459), in which the flanged portion of the valve is fixed to the fuel pump by the bolt, was intended to be applied to a fixing structure for a depressurizing valve to be mounted to the common rail, a bolt hole should be formed in the common rail of a cylindrical shape. In such a fixing structure, the direction of the connector provided in the depressurizing valve can be adjusted to a predetermined desired direction. However, it is actually difficult to form the bolt hole in the common rail, because the common rail is generally formed as the cylindrical shape, and thereby there is no sufficient space for the bolt hole.
In the fuel injection device disclosed in Japanese Patent Publication No. H11-141428, a direction of a connector portion can be adjusted by loosening a retaining nut. However, if the retaining nut was loosened, positions of inside parts, such as a spacer for adjusting an air gap, an armature, and so on would be changed. As a result, there would be a problem that the air gap would be changed after the retaining nut was once loosened and then tightly screwed again. Furthermore, if the retaining nut was loosened, a position and a contacting condition of a sealing member which is disposed between the retaining nut and the valve housing would be also changed. Accordingly, it would be necessary to check a sealing performance once again after the retaining nut was tightly screwed again.
In the case that the structure of the above prior art (Japanese Patent Publication No. H11-141428) for fixing the solenoid portion of the electromagnetic coil to the valve housing was applied to the depressurizing valve to be mounted to the common rail, the direction of the connector portion can be adjusted by loosening the retaining nut. However, there are still problems in that the air gap might be changed and/or the sealing performance should be checked again, as in the fuel injection device of the above mentioned prior art.